Abstract

Background

Several studies have evaluated the association between forest fire smoke and acute
exacerbations of respiratory diseases, but few have examined effects on pharmaceutical
dispensations. We examine the associations between daily fine particulate matter (PM2.5) and pharmaceutical dispensations for salbutamol in forest fire-affected and non-fire-affected
populations in British Columbia (BC), Canada.

Methods

We estimated PM2.5 exposure for populations in administrative health areas using measurements from central
monitors. Remote sensing data on fires were used to classify the populations as fire-affected
or non-fire-affected, and to identify extreme fire days. Daily counts of salbutamol
dispensations between 2003 and 2010 were extracted from the BC PharmaNet database.
We estimated rate ratios (RR) and 95% confidence intervals (CIs) for each population
during all fire seasons and on extreme fire days, adjusted for temperature, humidity,
and temporal trends. Overall effects for fire-affected and non-fire-affected populations
were estimated via meta-regression.

Results

Fire season PM2.5 was positively associated with salbutamol dispensations in all fire-affected populations,
with a meta-regression RR (95% CI) of 1.06 (1.04-1.07) for a 10 ug/m3 increase. Fire season PM2.5 was not significantly associated with salbutamol dispensations in non-fire-affected
populations, with a meta-regression RR of 1.00 (0.98-1.01). On extreme fire days PM2.5 was positively associated with salbutamol dispensations in both population types,
with a global meta-regression RR of 1.07 (1.04 - 1.09).

Conclusions

Salbutamol dispensations were clearly associated with fire-related PM2.5. Significant associations were observed in smaller populations (range: 8,000 to 170,000
persons, median: 26,000) than those reported previously, suggesting that salbutamol
dispensations may be a valuable outcome for public health surveillance during fire
events.